RF return optical transmission

ABSTRACT

A method of transmitting TV signals and bidirectional telephone communication signals on a single optical fiber, existing telephone twisted pair infrastructure, and existing coaxial cable infrastructure. In addition to allowing the downstream transmission of television channels as well as bidirectional telephone communication, the single optical fibers also provides for the upstream travel of television related signals while requiring minimal changes of the existing infrastructure.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to methods and apparatus forcarrying on simultaneous communications over a single optical fiber byusing two different operating frequencies, and more specifically tomethods and apparatus for use with WDM (wave division multiplexing) attwo different wavelengths of light to provide bidirectional telephoniccommunication using TDM (time division multiplexing) at one wavelengthof light and transmitting TV signals down stream only at anotherwavelength. TV control signals are returned by the telephoniccommunication path to the TV source by multiplexing the control signalswith the telephonic signals.

[0003] 2. Description of Related Art Including Information DisclosedUnder 37 CFR 1.97 and 1.98

[0004] The communications industry is using more and more optical orlight fibers in lieu of copper wire. Optical fibers have an extremelyhigh bandwidth thereby allowing significantly more information than canbe carried by a copper wire transmission line such as twisted pairs orcoaxial cable.

[0005] Of course, modern telephone systems require bidirectionalcommunications where each station or user on a communication channel canboth transmit and receive. This is true, of course, whether usingelectrical wiring or optical fibers as the transmission medium. Earlytelephone communication systems solved this need by simply providingseparate copper wires for carrying the communications in each direction,and this approach is still used in part of the transmission path. It isespecially used as the signals get closer to the end users. Althoughtwisted pairs and coaxial cables are used in homes and distributionterminals close to the home end user, some modern telecommunicationsystems now use micro-wave and optic fibers as transmission mediums. Inaddition TCM (time compression multiplexing) is often used in opticaltransmission so that a signal optical fiber can carry communications inboth direction.

[0006] However, because of extremely high band widths available for useby an optical fiber, a single fiber is quite capable of carrying a greatnumber of communications in both directions. One technique of opticaltransmission is WDM (wavelength divisional multiplexing) and usesdifferent wavelengths for each direction of travel.

[0007] Yet another and simpler technique for using a single opticalfiber for telephone systems is TCM (time compression multiplexing) andis sometimes referred to as a “ping-pong” system. The system operates ata single frequency or wavelength of light and uses a single opticalfiber and often even a single diode, for both converting electricalsignals to optical signals and converting received optical signals toelectrical signals. TCM systems have the obvious advantage of requiringfewer components.

[0008] However, as mentioned above, optical fibers have extremely highband widths and use of an optical fiber for a single ping-pong telephonechannel is a very ineffective use of the fiber and, in fact, theavailable bandwidth of an optical fiber makes it possible to use atransmission technique such as TCM or ping-pong at one frequency andthen by the use of WDM technology to use another technique at a secondfrequency.

[0009] Another area of rapidly growing technology is providingunidirectional TV signals by cable to a multiplicity of subscribers orusers. In the past, such signals were and still are typicallytransmitted by the use of coaxial cables (e.g. cable TV). However, theuse of optical fibers for transmission allows broad band transmission toa large numbers of customers and, since substantially all of thetransmission of TV signals is one way (i.e. unidirectional), if a singleoptical fiber were used solely for the TV signals there would be almostno use of the selected wavelength of light for carrying return signal,which are typically control or information signals.

[0010] Therefore, a technique for transmitting bidirectional telephonicsignals and unidirectional TV signals would make efficient use of anoptical fiber.

[0011] It would also be advantageous to provide return control signalsto the TV signal source or station with respect to each customer orsubscriber without having to dedicate a frequency or wavelength of lightfull time to said seldom used or RF Return transmitted signals.

SUMMARY OF THE INVENTION

[0012] The above objects and advantages are achieved in the presentinvention by methods and apparatus which comprise transmitting light ata first wavelength to carry telephonic signals between a firsttelephone-related device and a second telephone-related device, orlocation and also transmitting light at a second wavelength to carry TVsignals from a TV signal source to an end user(s). The wavelengths orlight are carried through a single optical fiber from a first-end to asecond-end. The first and second wavelengths of light are received atthe second-end of the optical fiber, and the signals on the firstwavelength of light are detected and converted to first electricalsignals at a first frequency band suitable for carrying telephonicsignals such as voice telephone and computer modem signal, at afrequency band of about 64 KHz. The received second wavelength of lightis also detected, and the detected light is converted to electricalsignals, within a second frequency band, typically between 5 and 800 MHZand are representative of TV channel signals. The telephonic electricalsignals are transmitted to a receiving telephone or othertelephone-related device and the electrical signals representative of TVsignals are transmitted to a TV signal receiving device. The returnelectrical telephonic signals are then generated at the receivingtelephone-related device at the same frequency band the originaltelephonic signal were transmitted and are representative of returntelephone information which could be modem information or voiceinformation. TV related electrical signals such as control signals,information signals or TV show ordering signals are also generated at athird frequency band. The return electrical telephonic signal at thefirst frequency band of about 64 HKz and the TV related electricalsignal generated at about 5 to 50 MHZ are multiplexed together. Themultiplexed electrical signals are converted to light signals at thefirst wavelength and carry both the return telephonic signal and the TVrelated signal. The light at the first wavelength is transmitted throughthe single optical fiber from the second end to the first end where itis received and detected such that electrical signals representative ofthe return telephonic signals and the electrical signal representativeof the TV related information are generated. The return electricaltelephonic signals are transmitted to the first telephone-related deviceand the electrical TV related signals are transmitted to the TV signalsource.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] These and other features of the present invention will be morefully disclosed when taken in conjunction with the following DetailedDescription of the Preferred Embodiment(s) in which like numeralsrepresent like elements and in which:

[0014]FIG. 1 is a prior art block diagram showing the presenttransmission and distribution of a typical coaxial TV and POTS telephonesystem;

[0015]FIG. 2 shows a POTS telephone system and a fiber optic TVdistribution system having 1550 nanometer light carrying TV signals inone direction and 1310 nanometers of light carrying telephonic signalsin both directions;

[0016]FIG. 3 shows a block diagram of a preferred embodiment of thepresent invention incorporating portions of the existing POTS telephonesystem and the coaxial TV signal distribution system while using asingle optical fiber for carrying the TV signals at 1550 nanometers oflight downstream and the telephonic signals in both directions at 1310nanometers; and

[0017]FIGS. 4A and 4B show detailed block diagram of the invention ofFIG. 3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

[0018] Referring now to FIG. 1, there is shown a typical transmissionand distribution system for cable TV and normal telephone service,referred to as POTS (plain old telephone service). As shown, cable TVsource location 10 has cable TV transmission equipment 12 which mayoriginate from several sources including a satellite receiver 14. The TVequipment 12 would then amplify this signal and send it out typically ona coaxial line such as line 16 to a distribution system which mayinclude several stations such as station 18 where the signal is againamplified and further distributed to an even larger multiplicity oflocations. Such re-amplification and further distribution may occurseveral times but eventually will arrive at a local distributionterminal 20 by means of a coaxial cable 12A from which it is thendistributed to a home or building 22 by a coaxial cable 12B. As showndistribution terminal 20 may also provide TV signals to other buildingsor homes such as indicated by bracket 24. Once the TV signal is receivedat building 22, it will then typically be provided to a TV set 26directly or to a set-top or cable TV box 28. If the signal is firstprovided to the set-top box 28, it is then directly provided to TV set26. It should be appreciated that the direction of travel for suchsignals is primarily unidirectional and downstream. That is, it travelsprimarily from the cable TV signal source 10 to the set-top box 28 inthe building or home 22 at frequencies of between 250-800 MHZ. Ifinformation is to be carried upstream or back to source 10, it willtypically be at between 50-200 MHZ.

[0019] Also shown is a typical telephone system or POTS which of courseis two-way communication typically carried by means of a twisted pair ofwires. In the example shown in FIG. 1, if someone at the cable TV signalsource location 10 wishes to talk with someone at building 22, thetelephone 30A is used in its normal manner. The two-way conversation iscarried on between the person in building 10 using telephone 30A and bya person using telephone 30B in the home or building 22. Thiscommunication is typically carried through a pair of twisted wires suchas indicated by 32, 32A, and 32B. In recent years, the regular telephonedistribution system has also been used to provide communications betweencomputers. This is done by the use of a modem 34 which connects acomputer to the telephone line. As was the case with the TV signaldistribution, there are typically several stations or substationsbetween the two telephones 30A and 30B located at the building 10 andthe building 22, respectively. Such distribution terminals or stationsallow telephone services between all subscribers with which we are allwell aware. However, as shown at distribution terminal 20A, there mayalso be several other buildings or homes connected to distributionterminal 20A as indicated by bracket 24A. As was discussed earlier,communications between buildings 10 and 22 were typically accomplishedthrough regular telephone service by individuals talking to each other.However with more efficient automation, telephone lines may also beconnected up to the set-top box 28 as indicated by wires 36. Inaddition, in the distribution terminal 38 at the cable TV signallocation, there is also a telephone connection to the TV signalequipment 12, such that it is now possible that movies or informationconcerning the TV signals and TV equipment can be communicated betweenthe two locations.

[0020] As demands increase for more and more TV channels and better andmore efficient transmission techniques without disruption andinterference, the long runs of coaxial cable are simply becominginefficient and inadequate. Thus as is shown in FIG. 2, there is animproved system for the transmission of TV signals between the TV signalsource location 10 and the building or home 22. In the systems shown inFIG. 2, there is also shown a standard telephone or POTS system asdiscussed above.

[0021] In the improved television transmission system, however, thetransmission is achieved by a fiber optical cable as indicated by fiberoptical cables 42 and 42A. As shown in FIG. 2, the same coaxial cable12B exist between the distribution terminal 20 and the home of building22. However, also as shown distribution terminal 20 includes newequipment 46 which receives the transmitted light on fiber optic 42 andconverts it to electrical signals and conversely receives electricalsignals from 12B and converts the electrical signals to light signalsfor transmission on fiber optic 42A. However as will be appreciated bythose skilled in the art, the TV signals from the TV signal sourcebuilding 10 normally travel downstream only and are continuous. Thus, ifbidirectional communications between the cable TV signal source 10 andthe distribution terminal 20 are to take place, some sort of sharing ofthe individual fiber optic 42A as well as the copper wire 12B must beprovided. Thus, in the example shown, the TV signals travel in a singledirection (i.e., downstream) from the TV signal source at location 10 tothe home or building 22 by light waves having a length of at 1550nanometers. Any return communication traveling on optical fibers 42 and42A must be carried at a different wavelength of light such as 1310nanometers which travels upstream to the TV signal source location 10.Likewise, if bidirectional communication is to take place on the singlecoaxial cable 12B between distribution terminal 20 and home or building22, the transmission of such bidirectional communication transmission beat different frequencies. Thus, in the illustrated example, the 1550nanometer light waves will be converted to electrical signals having afrequency band of between about 50 and 800 MHZ which travel in a singledirection from distribution terminal 20 to the home or building 22. Thereturn signals from the set or set-top box at building 22 are thencarried at about 5 to 50 MHZ back to the distribution terminal 20 andthen used to modulate light waves having a wavelength of 1310nanometers. Thus, it is seen that it is possible by the use of a singlefiber optic cable as well as using existing infrastructure copper wiringsuch as coaxial cable to transmit a broad frequency band of TV signalscarrying multiple channels of TV information at one wavelength of light.The individual TV channels are then converted to electrical signals at aspecific frequency within the 50-800 MHZ frequency band. Conversely,electrical control signals within the 5-50 MHZ frequency band areconverted to light at a wavelength different from that provided in thedownstream mode and transmitted back to the TV signal source location10. The return wavelength of light in the illustrated example is 1310nanometers.

[0022] Referring now to FIG. 3 there is shown a simplified block diagramof the preferred embodiment of the present invention which takes partialadvantage of the existing telephone and coaxial TV distribution systemswhile also using a single optical fiber 42A for part of the transmissionpath between the TV signal source location 10 and the building or home22. It should be noted that, although the following discussion is interms of a single path for the coaxial or optical fiber cable betweentwo locations 10 and 22, in actuality there may be a significant amountof multiplexing and de-multiplexing such that many, many subscribers orcustomers may be serviced by the single optical fiber and any othermultiplexed cable. It should also be noted that there may also beseveral amplification stations located at various locations in thedistribution path. As shown, TV signal source location 10 providessignals from equipment 12 and, in this illustrated embodiment, the TVsignals may be 50 to 800 MHZ signals provided on copper wire, such ascoaxial cable 16. Copper coaxial cable 16 carries the TV signals havinga band width of 50 to 800 MHZ to a distribution terminal 18 whichconverts the electrical TV signals to light signals having a selectedwavelength. In one preferred embodiment a particular selected wavelengthis 1550 nanometers. Thus the light waves travel in a single directionfrom distribution terminal 18 or distribution terminal 20. Also asshown, electrical telephonic signals may be carried by copper wires suchas copper wires 48 which represent a twisted pair of normal telephonecommunication wires to a substation 52 where electrical telephonicsignals traveling in one direction are converted to light signals at aselected frequency and light signals at that same frequency traveling inthe opposite direction are converted to electrical telephonic signals.Thus, the fiber optic cable 54 shown between distribution terminals 18and 52 carries telephonic signals at a single wavelength of lighttypically selected to be about 1310 nanometers. The light signals at1310 nanometers are able to travel in both directions on the singlefiber optic cable 54 by the use of TCM (time compression multiplexing).Although TCM is not normally suitable for higher density signals such asTV signals, it is quite adequate for lower frequencies suitable fortransmitting the human voice as well as frequencies up to about 50 to 64KHz, which is above human hearing. Time compression multiplexing simplystated means that time is broken up in substantially two portions orcycles such that signals travel in one direction during one portion andin the opposite direction during the other portion. Thus, distributionterminal 18 receives fiber optic cable 54 carrying the 1310 TCM (timecompression multiplexed) modulated light and also receives 50 to 800 MHZTV signals from the TV signal source location 10. The 50 to 800 MHZelectrical signals are converted to light signals having a wavelength of1550 nanometers. Thus, distribution terminal 18 also combines by WDM(wave division multiplexing) the 1310 nanometer signals with the 1550nanometer signal such that cable 42A carries 1550 nanometer signals in adownstream direction and carries 1310 nanometer telephonic signals inboth directions.

[0023] At distribution terminal 20, and as will be discussed in detaillater, the 1550 nanometer downstream traveling signals are thenreconverted to electrical TV signals having a band width of between 50and 80 MHZ. They are then distributed to various locations includinghome or building 22 as was discussed with respect to FIGS. 1 and 2above. In a similar manner, the bidirectional TCM signals traveling on1310 nanometer light waves are routed to other equipment in distributionterminal 20 which converts the 1310 nanometer light waves intoelectrical telephonic signals and converts electrical telephonic signalsinto light waves having a wavelength of 1310 nanometers. The electricaltelephonic signals are then distributed from distribution box 20 bytwisted wiring 32B to the telephone 30B or other telephonic equipmentsuch as the computer modem 34 at home or building 22.

[0024] As was discussed with respect to the system of FIG. 2 above, itmay be desirable to transmit certain types of television related controlsignals or “purchasing information” signals from the set-top box 28 orTV set 26 at building 22 back to the TV signal source location 10. Asdiscussed earlier with respect to FIG. 2, such return information willhave to be carried upstream at a different frequency band such as 2-50MHZ on the copper cable 12B and on a wavelength different than 1550nanometer on fiber optic cable 42A. Thus, in addition to the telephoneservice which travels on a wavelength of light of 1310 nanometers,distribution terminal 20 will also convert the 5 to 50 MHZ electrical TVrelated signals to light signals having a wavelength of 1310 nanometers.These light signals carrying the return TV related signals are thenmultiplexed with the telephone service also traveling at 1310 nanometersand the portion on the TCM cycle traveling from distribution terminal 20to distribution terminal 18. At distribution terminal 18, the TV relatedcontrol signals can be provided through fiber optic cable 1310 todistribution box 52 where they are converted to telephone electricalsignals and then provided in a normal fashion to the TV equipment 12 oralternately distribution terminal 18 may split out the 5 to 50 MHZsignals from the 1310 wavelength of light and provide the signal oncoaxial cable 16 which is carrying the downstream original televisionsignals having frequency bands of 50 to 800 MHZ. These 5-50 MHZ signalstraveling upstream go to the TV equipment 12.

[0025] Although in the embodiment shown in FIG. 3, the conversionbetween light waves and electrical signals for both telephone serviceand for TV signals is shown occurring at a remote distribution box 20,it will be appreciated that in the future it may be advantageous that asingle fiber optic would be connected into a home or building 22 and theconversion from electrical signal to light signals and vice versa willtake place in the building 22 itself as indicated by dotted line 55.

[0026] Thus, there has been discussed to this point generalized conceptsfor a new and improved telephonic and TV signal distribution systems.

[0027] Referring now to FIGS. 4A and 4B, there is provided a moredetailed description of the system of FIG. 3 discussed above. As shown,the TV signal source location 10 provides output TV signals at 50 to 800MHZ traveling downstream on copper wire 12. The electrical signals arethen provided to laser diode 56 where the electrical signal at 50 to 800MHZ are converted to light having a wavelength of 1550 nanometers. The1550 nanometer light is then eventually provided to a wave divisionmultiplexer 58 which is also connected to optical fiber 54 carryinglight at a wavelength of 1310 nanometers and will be discussed later.Although it is possible that the output of the light emitting diode 56could be provided directly to a wave division multiplexor 58, typicallythe light would go through a light amplifier such as EDFA (erbium dopedfiber amplifier) 60. The amplified light signal from amplifier 60 wouldthen pass the light through a first light splitting circuit 62 and thenagain perhaps to another light splitting circuit 64 such as a SWXcircuit. The output of the splitter 64 would then be provided to WDM 58.As shown, the output of WDM 58 is connected to light fiber 42A.

[0028] Also as shown, multiplexed telephone service POTS at the DS1level (i.e. information from up to 24 TV customers) on copper wire 65 isprovided to distribution box 52 wherein the electrical telephonicsignals typically having a frequency band up to about 60 MHZ areprovided to another laser diode 66. These electrical signals are thenconverted by laser diode 66 to light signals having a wavelength of 1310nanometers. This light is provided to optical fiber 54 as shown. As wasdiscussed earlier, telephone service is typically TCM (time compressionmultiplexing) so as to provide for bidirectional communication at asingle wavelength of light. Therefore as shown, light traveling upstreamand leaving optical fiber 54 is directed toward a photo or a lightdetection diode 68 which receives the light and converts the 1310nanometer light to telephonic signals having a frequency of about 60 KHzor less. Thus, the input electrical signal to laser diode 66 from line65 on the output electrical signal from light detector 68 on line 70Bactually represents a typical pair of twisted wires 71 used in normalPOTS telephonic service. In the embodiment shown, the output telephonicsignals on line 70A is first provided to a diplex circuitry 72 where theTV related control signals from the customer are split out on line 74and the regular telephonic communications such as voice and computermodem server continues on output line 70B. The 5-50 MHZ on line 74, isthen provided to a band pass filter circuit 70 which will only pass the5-50 MHz, and which has an output 78 provided to a combining circuitry80 which receives other similar signals from other TV customers up to atotal of at least 16 (8+8) customers. The output of combining circuitry80 is then provided to an 8 bit 90 MSPS (megsamples per second)analog-to-digital converter 81. The digital signals from A/D converter81 are then provided to a 90 MHZ 8 bit to 12 bit adder 82. Added 82 asshown can receive the output from 8 A/D converters such as A/D converter82. Thus, it will be appreciated that the output from adder 82 going tothe parallel to serial converter 84 will be carrying information relatedto at least 128 TV customers (16×8). The output of the P/S converter 84may then provided to another E/O (electrical-to-optical) device 86operating at 1 Gbps (giga bit per second). This output may then betransmitted by optical fiber 87 to CMTS (cable modem transmissionsource) at location 88 where the TV signal source 10 is also located.The light traveling through optical fiber 87 is then received by O/E(optical-to-electrical) converter 89 and the resulting electricalsignals are provided to S/P (serial-to-parallel) converter 90. Thisparallel digital information is then provided to D/A converter 92, whichin turn provides an analog signal to the TV signal source 10. Thisanalog signal may of course be a control signal or other informationrelated to a specific TV customer or subscriber.

[0029] Referring now to FIG. 4B, optical fiber 42A is shown beingreceived at distribution panel 20. As shown optical fiber 42A iscarrying television signals in one direction downstream by light havinga wavelength of 1550 nanometers at the same time it carriesbidirectional telephone communications using TCM (time compressionmultiplexing) by light having a wavelength of 1310 nanometers. As shown,the light having a wavelength of 1550 nanometers is directed towards aphoto detector 94 which converts this light to electrical televisionsignals having a band width of between 50 and 800 MHZ. These electricaltelevision signals are then provided by coaxial cable 96 to a diplexcircuit 98 which has an output 100 provided to splitting circuit 102.Also as shown and as will be discussed hereinafter diplex circuit 98also separates out electrical signals having a frequency of between 5and 50 MHZ traveling in the opposite direction. One of the outputs ofsplitter or distribution circuit 102 carrying the 50 to 800 MHZelectrical signals will then be provided to building or house 22 bymeans of coaxial cable 12B in the manner previously discussed. Thetelevision signals on coaxial cable 12B are then either provided to TVset 20 or to another TV-signal using device such as set-top box 28, andthen to TV set 26. Also, in the building 22 there is shown a computer104 connected to a computer modem 34 as was discussed heretofore withrespect to FIG. 1 and which is also connected to the standard telephonelines or POTS lines 32B. Also as shown, a telephone 30B is connected tothe POTS lines 32B. The RF return or TV related signals sent back to theTV source location 10 may result from several sources. One possiblesource is for the set-top box 28 to sense that the television signalsbeing received need to be either decreased or increased in amplitude orstrength. Alternately, it may be that the customer or user of thetelevision decides to purchase a particular pay-on-demand movie. Stillanother source of information may be an input from the computer 104provided to the set-top box carrying information or requestinginformation. Such information must be provided back to the TV sourcelocation 10. Set-top box 28 will convert the information into anelectrical signal having a frequency band of between 5 and 50 MHZ whichis inserted on coaxial cable 12B and transmitted to distributionterminal 20. It will be appreciated that coaxial cable 12B can carryinformation in both directions if the frequency band for the twodirections is sufficiently separated. The 5-50 MHZ television relatedsignals are then routed to the diplex circuitry 98 where the electricalsignals having a frequency band of 5 to 50 MHZ are split out andprovided to another combining multiplexing circuit 106.

[0030] Now referring again to the input cable 42A which, in addition tocarrying light having a wavelength of 1550 nanometers as was previouslydiscussed, is also carrying light at 1310 nanometers for thebidirectional telephone communication using TCM (time compressionmultiplexing). Thus, the light having a wavelength of 1310 nanometer issplit and provided to a photo detector 108 which converts the 1310nanometer light traveling downstream to telephonic electrical signalswhich travel on wires 109. These telephonic electrically signals willtypically be POTS signals at the DS1 (up to 24 customers) or DS2 (up to96 customers) level and are provided to the multiplexer 110 andeventually by means of wires 32B to the telephone circuitry in house orbuilding 22. It should be appreciated that the wire 32B connecting home22 to the distribution panel 20 is a normal twisted pair of telephonewires. The upstream traveling POTS service travels on wire 111 tomultiplex circuit 106 where it is combined with the 5 to 50 MHZ signalsand provided on output line 112 to a laser diode 114. Laser diode 114then converts the electrical signals carrying the 5 to 50 MHZ televisionrelated signals as well as the telephonic signals to light having awavelength of 1310 nanometers which light is then coupled again to fiberoptic 42A. Thus, as was discussed earlier, the fiber optic 42A carriesthe upstream traveling 1310 nanometer light to distribution panel 18where it is split out for both telephonic service and television relatedsignal service.

[0031] Thus, there has been discussed to this point a new and novelcommunication transmission system using a single optical fiber as partof the communication path along with parts of an existing telephonecommunication system and parts of an existing cable TV distributionsystem.

[0032] The corresponding structures, materials, acts, and equivalents ofall means or step plus function elements in the claims below areintended to include any structure, material, or act for performing thefunction in combination with other claimed elements as specificallyclaimed.

I claim:
 1. A method of providing TV signals or multiple of subscribersand bidirectional telephonic communications to a multiplicity ofsubscribers through a single optical fiber comprising the steps of:transmitting light at a first wavelength carrying telephonic signalsfrom a first plurality of telephone related devices and at a secondwavelength carrying TV signals from a TV signal source through anoptical fiber from a first end to a second end; receiving said firstwavelength of light and generating first electrical signals within afirst frequency band and representative of said plurality of telephonicsignals; receiving said second wavelength of light and generating secondelectrical signals within a second frequency band and representative ofsaid TV signals; transmitting said telephonic electrical signals to aplurality of telephone related devices and said second electricalsignals to a plurality of TV signal receiving devices; generating aplurality of return electrical telephonic signals at said firstfrequency band representative of return telephonic information and aplurality of TV related electrical signals at a third frequency bandrepresentative of TV related information from said plurality ofsubscribers; multiplexing said electrical signals carrying said returntelephonic signals at said first frequency band and said TV relatedelectrical signals carrying said TV related information at said thirdfrequency band; receiving said multiplexed electrical signals andgenerating light at said first wavelength representative of said returntelephonic signals and said TV related information; transmitting lightat said first wavelength and carrying said return telephonic signals andsaid TV related information through said optical fiber from said secondend to said first end; receiving said light carrying said returntelephonic signals and said TV related information and generating aplurality of third electrical signals representative of said returntelephonic signals and a plurality of fourth electrical signalsrepresentative of said TV related information; and transmitting saidthird electrical signals to said first plurality of telephone relateddevices and said fourth electrical signals to said TV signal source. 2.The method of claim 1 wherein said first wavelength of light is 1310nanometers and said second wavelength of light is 1550 nanometers. 3.The method of claim 1 wherein said highest frequency of said firstfrequency band is less than about 60 KHz.
 4. The method of claim 3wherein said third frequency band is between about 5 and about 50 MHZ.5. The method of claim 4 wherein said second frequency band is betweenabout 50 MHZ and about 800 MHZ.
 6. A method of communicating comprisingthe steps of: transmitting light at a first wavelength carrying firstinformation from a first source and a second wavelength carrying secondinformation from a second source through an optical fiber from a firstend to a second end; receiving said first wavelength of light andgenerating first electrical signals at a first frequency band andrepresentative of said first information; receiving said secondwavelength of light and generating second electrical signals at a secondfrequency band and representative of said second information;transmitting said first electrical signals to a first device and saidsecond electrical signals to a second device; generating thirdelectrical signals at said first frequency band representative of thirdinformation and fourth electrical signals at a third frequency bandrepresentative of fourth information; multiplexing said third electricalsignals and said fourth electrical signals; receiving said multiplexedelectrical signals and generating light at said first wavelengthrepresentative of said third and fourth information; transmitting lightat said first wavelength carrying said third and fourth informationthrough said optical fiber from said second end to said first end;receiving said light carrying said third and fourth information andgenerating fifth electrical signals representative of said thirdinformation and sixth electrical signals representative of said fourthinformation; and transmitting said fifth electrical signals to saidfirst source and said sixth electrical signals to said second source. 7.Communication signal transmission apparatus for carrying unidirectionalTV signals downstream from a source to a first user and for carrying TCM(time compression modulation) bidirectional telephonic signals betweensaid first user and a second user comprising; an optical fiber suitablefor simultaneously carrying two distinct wavelength of light by WDM(wave division multiplexing) between a first location and a secondlocation; conversion apparatus located at said second location andconnected to said optical fiber, said conversion apparatus convertingoptical signals at said first wavelength of light and carrying saidunidirectional TI signals to electrical TV signals at a first frequency,converting optical signals at said second wavelength of light andcarrying said TCM bidirectional telephonic signals to electricaltelephonic signals, and converting electrical telephonic signals to TCMbidirectional telephonic optical signals at said second wavelength oflight; a first electrical conductor for receiving and carrying TVsignals at said first frequency from said second location to a TV signaluser device; TV related signals at a second frequency generated by saidTV signal user device connected to said first electrical conductor andtransmitted from said TV signal user device at said second location; apair of electrical conductors for receiving and carrying saidbidirectional telephonic signals between said second location and a userdevice; a multiplexer for combining said TV related signals and saidbidirectional telephonic signals to produce said electrical telephonicsignals converted to optical signals at said second wavelength of lightby said conversion apparatus; a TV signal source connected to saidoptical fiber at said first location to modulate said first wavelengthof light; a second converting device for converting electrical signal tooptical signals at said first wavelength of light and optical signal atsaid second wavelength of light to electrical signals; and a secondtelephonic signal user device for sending and receiving saidbidirectional telephonic signals.